1. Field of the Invention
The present invention generally relates to power supply control apparatuses of navigation systems. More specifically, the present invention relates to a power supply control apparatus of a navigation system including a power switch for a display screen that a user can switch on and off.
2. Description of the Related Art
Conventionally, a navigation system is known that detects a vehicle position, shows a path to a goal and the like on a display screen by a map and provides own vehicle position information and goal information for a user. The navigation system often includes a display screen power switch for a user that can switch the display screen on and off in terms of providing information only when the user wants display information.
On the other hand, once a power supply of the navigation system is completely turned off, it takes a certain amount of time to rise up (reboot) like a personal computer. Hence, in terms of maintaining responsiveness of an apparatus, even when the display screen power switch is turned off, an internal function of the navigation system itself often keeps working, receiving GPS (Global Positioning System) data and the like. This allows the navigation system to show and provide map information including the own vehicle position for the user when the user needs the information of the navigation system and turns on the display screen power switch.
However, in the above-mentioned conventional navigation system, even if the user turns off the display screen power switch, since the navigation system shows only a black image on the display screen and the usual internal function such as a own vehicle position search continues to work, electric power is consumed as well as in a case where the display screen power switch is turned on.
On the other hand, there is a case where the information of the navigation system is apparently not needed such as a case where the user checks an engine room leaving an engine operating, or a case where vehicle stability control and the like are performed because a vehicle skids. Moreover, the user may want to completely turn off all functions of the navigation system to cut wasteful power consumption when the user does not need the information of the navigation system at all. Even in such a case, the conventional navigation system does not entirely shut down due to terms of emphasizing responsiveness, but continues to consume electric power as well as that while normally working, which has prevented improving gasoline mileage.
As a similar technique, a drive control apparatus of an operating vehicle is disclosed in Japanese Patent Application Laid-Open Publication No. 08-268105, where an engine automatically stops when a hood is opened, and the stopped engine can enter a workable state where a human operation is performed. Furthermore, the workable state is automatically canceled once the hood is closed, and the engine can be automatically stopped again when the hood is opened next.